Corrigendum to “Regulation of the paracellular Na+ and Cl− conductances by the NaCl-generated osmotic gradient in a manner dependent on the direction of osmotic gradients” [Biochem. Biophys. Res. Commun. 366 (2008) 464–470]

The author regrets errors in the Abstract. The Abstract is correct as it appears below: In the present study, we investigated the effect of osmolality on the paracellular ion conductance (Gp) composed of the Na conductance (GNa) and the Cl conductance (GCl). An osmotic gradient generated by NaCl with relatively apical hypertonicity (NaCl-absorption-direction) induced a large increase in the GNa associated with a small increase in the GCl, whereas an osmotic gradient generated by NaCl with relatively basolateral hypertonicity (NaCl-secretion-direction) induced small increases in the GNa and the GCl. These increases in the Gp caused by NaCl-generated osmotic gradients were diminished by the application of sucrose canceling the NaCl-generated osmotic gradient. The osmotic gradient generated by apical application of sucrose without any NaCl gradients had little effects on the Gp. However, this apical application of sucrose produced a precondition drastically quickening the time course of the action of the NaCl-generated osmotic gradient on the Gp. Further, we found that application of the basolateral hypotonicity generated by reduction of NaCl concentration shifted the localization of claudin-1 to the apical from the lateral side. These results indicate that the osmotic gradient regulates the paracellular ion conductive pathway of tight junctions via a mechanism dependent on the direction of NaCl gradients associated with a shift of claudin-1 localization to the apical side in renal A6 epithelial cells.